Is it possible to disable the startup sound on an iMac G5, or at least decrease its volume?

The obvious way to do this would be to put a script in the shutdown folder (OS X 10.4.11) that mutes the sound, then put one in the startup folder that reverses it. Unfortunately, I've been unable to find a "mute" script.

A Firewire audio interface plugged in on startup will route the startup sound to the external device. I'm not sure if this works with USB audio.
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Neil FeinJan 7 '11 at 17:25

...also, I'm not certain this is correct. Aside from the scenario in my above comment, muting the startup noise before shutting down will make the startup noise go away when restarting, no hardware required. I think my question should have been, How can you set the system to mute with a script?
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Neil FeinJan 7 '11 at 17:27

Unfortunately, this doesn't work on my Mac. Would downvote, but I don't have the rep yet. (If this works on some Macs and not others, you might consider going into more detail; this would be an extremely handy piece of info for users of the Macs it does work on.)
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Neil FeinJan 25 '11 at 19:49

No need to down-vote, as this has worked on every Mac since at least Mac OS X - if it does not work on your Mac, would you be so kind and comment on what kind of Keyboard you use (Apple, other Vendor, wired, wireless,…) and also whether turning down the volume completely before rebooting stops your Mac from playing the chime? If the latter is not the case, please try resetting your parameter RAM, as described here: support.apple.com/kb/HT1379?viewlocale=en_US
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AsmusJan 26 '11 at 16:58